Increasing cancer mortality among opioid-dependent persons in Australia : a new public health challenge for a disadvantaged population

The aim of this study was to examine cancer mortality in a population-based cohort of opioid dependent persons. New South Wales opioid substitution therapy (OST) program registrants from 1985 to 2005 (n=43,789) were probabilistically linked to the National Death Index. Crude and standardised mortality rates and standardised mortality ratios (SMRs) were calculated. The crude cancer mortality rate increased from 4 to 65 deaths per 100,000 person-years (p trend <0.001). Overall, OST registrants were 1.7 times more likely to die of cancer than the general population (SMR 95% CI 1.4-1.9). Site-specific SMRs were significantly elevated for lung cancer (3.6, 95% CI 2.8-4.6), liver cancer (6.9, 95% CI 4.3-10.5), and anogenital cancers (2.8, 95% CI 1.3-5.3), and significantly reduced for breast cancer (0.4, 95% CI 0.1-0.9). Cancer is an increasingly important cause of death among OST registrants as they live longer with their dependency. The site-specific excess deaths suggest the role of tobacco, alcohol, and infection with hepatitis C and human papillomavirus. The OST setting may be a useful setting for the delivery of programs aimed at detection of precursor lesions, reducing exposure to established carcinogens, and treatment for those with HCV infection. Such targeted steps are likely to reduce the future cancer burden in this population.